Snap-on light socket



0. P. CH'RISTENBERY 2,800,635

SNAP-ON LQIGHT SOCKET Filed March 25, 1956 INVENTOR.

' DOLDHUS P. C\-\\Z\5TENBE2Y ATTQRNEYS July 23,1957

2,869,635 Patented July 23, 1957 2,8i il,635

SNAP-(3N LIGHT SUQKET Doiphus P. Christenbery, Royal Oak, Mich.

Application March 23,1956, SerlalNo. 573,414

3 vClaims. (Cl. 339-99 This invention relates to electric light sockets,and more particularly has reference to a socket for a lamp bulb capableof connection to a standard two-conductor cord at any location along thelength of the cord, in a manner to provide an electrical connectionbetween the lamp bulb and the cord.

Summarized briefly, the invention comprises a socket including alamp-receiving section and a base section, adapted to interfit bysnapping of the base section onto the bulb retainer or lamp-receivingsection. Confronting, complementary recesses are formed in thecontacting faces of the cap or base section, and bulb retainer orlamp-receiving section, defining channels adapted to receive a standard,two-conductor, household electric ex tension cord. Projecting into therecesses of the bulb retainer are prongs adapted to penetrate theinsulation of the cord to engage the leads of the cord, the prongs beingcarried by a disc axially shiftable within the bulb retainer, said discbeing spring-biased in a direction to normally retract the prongs fromthe bulb retainer recesses. The disc includes a first terminal adaptedto contact the base contact of the lamp bulb, and a second terminaladapted to contact the cylindrical side Wall of the bulb.

in accordance with the invention, the prongs do not penetrate the corduntil a bulb is screwed into the bulb retainer, the inserted bulbbiasing the disc against the restraint of the associated springs in adirection to extend the prongs into the mentioned channels.

Among important objects of the invention are the following:

To provide a socket so designed that it can be used whenever a string oftemporary lights are wanted, thus particularly adapting the socket foruse in Christmas decoration lighting, although obviously many other usesthereof are possible:

To provide a socket which can be snapped onto any standard, household,electric extension cord;

To permit spacing of sockets to dispose them at any desired locationsupon the cord;

To permit as many sockets as desired to be used on a single cord, up tothe capacity of the cord;

To permit removal of the sockets from the cord for facility in storage;

To allow the cord to be put toany other use after removal of thesockets, since the sockets do not damage the cord;

To eliminate the danger of electric shocks incurred by contact withsockets in which bulbs have not been inserted due to the fact that thesocket will not function without a bulb;

To provide a socket which, should one socket be damaged, will not affectadversely the use of the remaining sockets of the string;

To provide a socket that can be used out-of-doors; and

To provide a socket which can be obtained individually, so that one maypurchase as many as desired, rather than being compelledto purchase afull string of lights having a predetermined number of sockets.

Other objects will appear from the following description, the claimsappended thereto, and from the annexed drawing, in which like referencecharacters designate like parts throughout the several views, andwherein:

Figure 1 is a perspective view of a fragmentary portion of a standardextension cord, to which a pair of the sockets have been connected;

Figure 2 is an enlarged section on line 22 of Fig ure 1;

Figure 3 is a sectional view on the same cutting plane as Figure 2, withthe bulb removed and the prongs contracted;

Figure 4 is a transverse sectional view on line 44 on the same scale asFigure 3; and

Figure 5 is an exploded perspective view of the socket per se.

Referring to the drawings in detail, designated generally at lti is alamp socket formed according to the present invention. This includes agenerally cylindrical bulb retainer body 12 having an axial recess forreceiving a bulb, said recess opening upon the outer end of the retainerbody. The bulb retainer body, adjacent its inner end, has an externallyreduced, cylindrical portion 14, merging into a circular flat bulbretainer base 16 the periphery of which projects beyond or overhangs theportion 14 to provide a circumferential lip upon the base 16 of the bulbretainer body.

At its opposite ends, the bulb retainer body is formed with a flaredportion -15 into which the globe portion of i the bulb extends.

Fixedly mounted within the axial recess of the bulb retainer body 12 isa threaded, electrically conductive liner 2s, said liner terminating atits inner end a substantial distance inwardly from the inner end of therecess. Beyond the inner end of the liner 26, within the recess, thereis provided a flat, circular disc 22 of electrically insulativematerial, lying in a plane normal to the axis of the bulb retainer body.The disc has limited movement in a direction axially of the bulbretainer body, between the inner end of the recess and an internalshoulder 24- formed upon the wall of the recess beyond the inner end ofliner 20.

Integral or otherwise made rigid with the disc 22, at diametricallyopposite locations thereon, are guide lugs 26. These extend parallel tothe axis of the bulb retainer body, and have free ends slidably engagedin lug sockets 23 formed in the inner end wall of the recess.Compression coil springs are seated in the lug sockets, and exert acontinuous pressure on the lugs tending to bias the disc 22 toward theopen end of the recess of the retainer body, into engagement with thelip 24 as shown in Figure 3.

Communicating between the axial recess of the bulb retainer body andside-by-side, parallel channels 34 formed in the outer face of the base16 (see Figure 5) are small diameter bores 32, and slidable in saidbores are conductive prongs 36. One of the prongs 36 is connected to acenter contact 38 mounted in the disc and faced toward the open end ofthe bulb retainer body. The other prong is connected to a resilientelongated, conductive member 40 of zig-zag shape connected to theconductive liner 20.

A circular cap 46 of electrically insulative material is formed with aperipheral flange having an inwardly facing, circumferential groove 48adapted to receive the lip of the base 16. The material of which the capis formed is slightly resilient, so that the cap can be snapped ontosaid lip.

The cap is formed, on its inner surface, with side-byside parallelchannels 50, matching the channels 34 so that when'the cap is snappedonto the bulb retainer body,

the channels 34, 50 will cooperate to define side by side passagesextending transversely of the socket constituting the present invention.In a commercial embodiment, instead of side by side channels 34 andcorresponding channels 50, there might be a single, relatively widechannel 34 in the base 16 and a single, complementary channel 50 in thecap, the channels being of a width such as to permit an electric cord42, of the conventional flat, two-conductor type regularly used as ahousehold extension cord, to be inserted. 7

In any event, the passages defined by snapping of the cap onto the bulbcontainer body form a conduit within said body open at both its ends andextending transversely of the body, through which the cord 42 extends.

In use of the invention, the prongs will initially retract from theconduit as shown in Figure 3, since the springs 30 are free to expandand shift the disc against the lip or shoulder 24. When, however, a lampbulb 44 is screwed into the socket with the cord 42 seated in theconduit and the cap snapped onto the bulb retainer body, the base of thelamp bulb will ultimately engage the contact 38 and on further threadingof the lamp bulb to its maximum extent, as shown in Figure 2, said bulbwill shift the disc 22 inwardly against the restraint of springs 30.'This will cause the prongs 36 to be projected into the conduit of thecord 42, and the prongs, being sharply tipped at their free ends, willpenetrate the insulation of the cord and engage the electricallyconductive leads of the cord as shown in Figure 2.

This results in an electrical connection between the cord and the lampbulb, responsive merely to threading of the bulb into the bulb retainerbody, and further, when the bulb is threaded out of the body, thesprings will now be free to expand, and will urge the disc 22 back toits normal position shown in Figure 3, to retract the prongs so thatthere will be no danger of an accidental electric shock should oneextend his or her finger into the recess of the bulb retainer body.

It will be readily apparent that any number of sockets can be used upona single cord, up to the capacity of the cord, and further, standardhousehold electric extension cords can be employed, and can be placedback in regular use merely by removal of the sockets.

Further, the sockets can be spaced along the cord as desired, and inaddition, there is achieved the desirable result wherein the electricalconnection is made in a protected location within the socket, thusparticularly adapting the device for use out-of-doors, where it isexposed fully to the elements. 7

It is believed apparent that the invention is not necessarily confinedto the specific use or uses thereof described above, since it may beutilized for any purpose to which it may be suited. Nor is the inventionto be necessarily limited to the specific construction illustrated anddescribed, since such construction is only intended to be illustrativeof the principles, it being considered that the invention comprehendsany minor change in construction that may be permitted within the scopeof the appended claims. o

What is claimed is: x

1. A snap-on lamp socket for attachment to an electrical .conductorhaving a pair of insulated, side-by-side leads, comprising: acylindrically shaped, electrically insulative, bulb retainer body havinga threaded recess opening upon one end of the body to receive thecomplementarily threaded base of a lamp bulb; a conductive elementengaged with the side wall of the body within the recess for contactingthe side wall of the lamp bulb base, the body having at its other end anend wall fully closing the body at said other end thereof andvhaving apermanent, fixed, connection to the side Wall of the body, said end wallhaving an outer surface formed with sideby-side channels in which saidleads may be placed, the

of the end wall; a cap proportioned to overlie the end wall and having apair of channels corresponding to those of the end wall to cooperatewith the end Wall channels in receiving said leads, said cap including acircumferential flange formed of a resilient, yielding material andhaving an inwardly opening, undercut groove mating with said first namedflange, thus to clamp the leads between the cap and end wall responsiveto resilient spreading of the flange of the cap over the flange of theend wall into a position gripping said flange of the end wall; a disc ofelectrically insulative material shiftable axially of the body andspring-biased in one direction in the recess of the body, said discbeing disposed to be shifted in an opposite direction by the insertedlamp bulb, against the restraint of the spring bias of the disc; a pairof prongs carried by said disc and disposed to enter the channels of theend wall on shifting of the disc in said opposite direction, topenetrate the conductor for contacting the leads; and a contact carriedby one of the prongs and disposed for engagement by the center contactof the inserted lamp bulb, the other prong having an electricalconnection to said conductive element, thus to provide a circuit throughthe bulb responsive to threading of the bulb into the socket.

2. A snap-on lamp socket for attachment to an electrical conductorhaving a pair of insulated, side-by-side leads, comprising: acylindrically shaped, electrically insulative, bulb retainer body havinga threaded recess opening upon one end of the body to receive thecomplementarily threaded base of a lamp bulb; a conductive elementengaged with the side wall of the body Within the recess for contactingthe side wall of the lamp bulb base, the body having at its other end anend wall fully closing the body at said other end thereof and having apermanent, fixed, connection to the side wall of the body, said end wallhaving an outer surface formed with sideby-side channels in which saidleads may be placed, the end wall being formed with a continuous,circumferential flange projecting outwardly from the body in the planeof the end wall; a cap proportioned to overlie the end wall and having apair of channels corresponding to those of the end wall to cooperatewith the end wall channels in receiving said leads, said cap including acircumferential flange formed of a resilient, yielding material andhaving an inwardly opening, undercut groove mating with said first namedflange, thus to clamp the leads between the cap and end wall responsiveto resilient spreading of the flange of the cap over the flange of theend wall into a position gripping said flange of the end wall; a disc ofelectrically insulative material shiftable axially of the body andspring-biased in one direction in the recess of the body, said discbeing disposed to be shifted in an opposite direction by the insertedlamp bulb, against the restraint of the spring bias of the disc; a pairof prongs carried by said disc and disposed to enter the channels of theend wall on shifting of the disc in said opposite direction, topenetrate the conductor for contacting the leads; and a contact carriedby one of the prongs and disposed for engagement by the center contactof the inserted lamp bulb, the other prong having an electricalconnection to said conductive element, thus to provide a circuit throughthe bulb responsive to threading of the bulb into the socket, saidchannels of the end wall and cap being disposed in closely spaced,parallel relation with one at least of the channels being extendedsubstantially diametrically of the end wall, the channels beingcontinuous fully across the end wall and cap with the leads being whollyenclosed by the cap and end wall over the full transverse dimension ofthe end wall.

3. A snap-on lamp socket for attachment to an electrical conductorhaving a pair of insulated, side-by-side leads, comprising: acylindrically shaped, electrically insulative, bulb retainer body havinga threaded recess opening upon one end of the body to receive the com-.plementarily threaded base of a lamp bulb; a conduc- 5 tive elementengaged with the side wall of the body within the recess for contactingthe side wall of the lamp bulb base, the body having at its other end anend wall fully closing the body at said other end thereof and having apermanent, fixed, connection to the side wall of the body, said end wallhaving an outer surface formed with side-by-side channels in which saidleads may be placed, the end wall being formed with a continuous,circumferential flange projecting outwardly from the body in the planeof the end wall; a cap proportioned to overlie the end wall and having apair of channels corresponding to those of the end wall to cooperatewith the end wall channels in receiving said leads, said cap including acircumferential flange formed of a resilient, yielding material andhaving an inwardly opening, undercut groove mating with said first namedflange, thus to clamp the leads between the cap and end wall responsiveto resilient spreading of the flange of the cap over the flange of theend wall into a position gripping said flange of the end wall; a disc ofelectrically insulative material shiftable axially of the body andspringbiased in one direction in the recess of the body, said disc beingdisposed to be shifted in an opposite direction by the inserted lampbulb, against the restraint of the spring bias of the disc; a pair ofprongs carried by said disc and disposed to enter the channels of theend wall on shifting of the disc in said opposite direction, topenetrate the conductor for contacting the leads; and a contact carriedby one of the prongs and disposed for engagement by the center contactof the inserted lamp bulb, the other prong having an electricalconnection to said conductive element, thus to provide a circuit throughthe bulb responsive to threading of the bulb into the socket, saidchannels of the end wall and cap being disposed in closely spaced,parallel relation with one at least of the channels being extendedsubstantially diametrically of the end wall, the channels beingcontinuous fully across the end wall and cap with the leads being whollyenclosed by the cap and end wall over the full transverse dimension ofthe end wall, the prongs entering the channels of the end wall mediallybetween opposite ends of said channels of the end wall, so as to effectpenetration of the insulation of the conductor at locations inwardly asubstantial distance from the outer surfaces of the cap and body.

Smith Feb. 14, 1916 Gilbert July 28, 1953

